Film formation apparatus

ABSTRACT

An apparatus includes: a rotatable table for revolving a substrate mounting region on which a substrate is mounted about a rotational center thereof; a first gas supply part for supplying a source gas to a first region through injection portions formed to face the rotatable table; an exhaust part for exhausting a gas through an exhaust port; a second gas supply part for supplying a separation gas for separating inner and outer sides of a second closed path from each other; a third gas supply part including two gas injectors arranged to extend at a certain interval in the crossing direction; a plasma generation part for reaction gas for plasmarizing the reaction gas injected toward the second region; and other process regions in which processes different from the supply of the source gas and the supply of the reaction gas are performed.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of Japanese Patent Application No.2015-252064, filed on Dec. 24, 2015, in the Japan Patent Office, thedisclosure of which is incorporated herein in its entirety by reference.

TECHNICAL FIELD

The present disclosure relates to a technology for forming a thin filmby supplying a source gas and a reaction gas reacting with the sourcegas to a surface of a substrate.

BACKGROUND

As a method of forming a thin film on a semiconductor wafer (hereinafterreferred to as a “wafer”) as a substrate, a plasma enhanced atomic(molecular) layer deposition (PE-ALD (MLD)) (hereinafter, ALD and MLDare collectively referred to as “ALD”) is known. In such a PE-ALD, awafer is exposed to a source gas containing a precursor of a thin filmsuch that the source gas containing a constituent element of the thinfilm is adsorbed onto the wafer. Then, the wafer onto which the sourcegas is adsorbed is exposed to plasma of a reaction gas. The reaction gasdecomposes the aforementioned precursor or supplies other constituentelements capable of being coupled to the constituent element of theprecursor, thereby to form a desired atom layer or molecular layer onthe wafer. In the PE-ALD, a thin film in which the atom layers or themolecular layers are deposited by repeating the above processes isformed on the wafer.

As an apparatus for performing the PE-ALD, a sheet-wafer type filmformation apparatus and a semi-batch type film formation apparatus areknown. In the sheet-wafer type film formation apparatus, wafers areloaded into a vacuum container one by one, and a source gas and areaction gas are alternately supplied into the vacuum container. In thesemi-batch type film formation apparatus, an inner space of a vacuumcontainer is partitioned into a region to which a source gas is suppliedand a region to which a reaction gas is supplied, and waferssequentially pass through these regions. The semi-batch type filmformation apparatus supplies the source gas and the reaction gas indifferent regions, thus simultaneously processing a plurality of wafers.Thus, the semi-batch type film formation apparatus is advantageous inthat it has higher throughput than the sheet-wafer type film formationapparatus.

For example, the present inventors developed a first semi-batch typefilm formation apparatus, in which a rotatable table (mounting stand)that is rotatable around an axis thereof is installed inside a vacuumcontainer (this is expressed as a “process container” in the related artand this expression is similarly applied even in the Background sectionof the present disclosure), and the interior of the vacuum container ispartitioned into a first region to which a source gas (precursor gas) issupplied and a second region to which a plasmarized reaction gas issupplied. A plurality of wafers is arranged on the rotatable table in acircumferential direction. With the rotation of the rotatable table,each of the wafers repeatedly passes through the first and secondregions in an alternate manner so that a film formation process isperformed on each of the wafers.

In such a first film formation apparatus, the first region is configuredas a fan-shaped space defined by partitioning a portion of a circularspace above the rotatable table in the circumferential direction, andthe second region is defined by the remaining space. The first region isseparated from the second region by an exhaust port formed to surrounddischarge portions (injection portions) from which the source gas issupplied, and a separation gas supply port (injection port) formed tosurround the exhaust port and supply a separation gas (purge gas)therethrough.

According to this film formation apparatus, the second region to whichthe reaction gas is supplied and requires a longer reaction time than atime required in adsorbing the source gas, is increased in size, thusforming a thin film having good film quality.

On the other hand, there may be a case where the thin film thus formedincludes a portion in which coupling between atoms constituting the thinfilm is not sufficiently achieved. As such, for example, after a filmformation process is completed, there is a need to stop the supply ofthe source gas and perform a post-process which includes switching a gasto be plasmarized to a post-process gas such as hydrogen, and couplingdangling bonds of atoms in the thin film to densify the thin film.

However, if the post-process that switches the gas to be supplied intothe vacuum container is additionally performed after the film formationprocess, a period of time from when a wafer is carried into a filmformation apparatus till when the wafer is carried out of the filmformation apparatus is prolonged, which causes deterioration in processefficiency of the film formation apparatus.

Moreover, there is a case where a reaction gas immediately afteradsorbed onto the wafer contains impurities derived from a precursor. Atthis time, a pre-process of removing the impurities with a pre-processgas containing a plasmarized hydrogen or the like is performed beforecausing a source material adsorbed onto a substrate to react with thereaction gas, which makes it possible to improve a film quality of athin film. However, in the first film formation apparatus according tothe related art, since the regions (the first region and the secondregion) inside the vacuum container are filled with the source gas orthe reaction gas, it is difficult to perform such an impurity removalprocess during a time period from when the source gas is adsorbed ontothe substrate till when the source gas reacts with the reaction gas.

In addition, there is known a second semi-batch type film formationapparatus in which an activation gas injector is installed in adirection crossing a movement direction of wafers that arecircumferentially arranged on a rotatable table. However, the secondfilm formation apparatus has a structure in which a portion of a ceilingsurface constituting a vacuum container is formed to approach therotatable table so as to form a restricted space. This structureseparates regions (process regions) to which different gases aresupplied. Accordingly, the second film formation apparatus is differentin type from the first film formation apparatus.

Thus, the second film formation apparatus does not describe theconfiguration in which the aforementioned pre-process or post-processcan be performed inside a film formation apparatus in which the interiorof a vacuum container to which a reaction gas is supplied is notpartitioned into a plurality of spaces as in the second region of thefirst film formation apparatus.

SUMMARY

Some embodiments of the present disclosure provide a film formationapparatus capable of performing other processes different from supplyinga reaction gas in the interior of a vacuum container which includes afirst region to which a source gas is supplied and a second regionpartitioned from the first region and to which a plasmarized reactiongas reacting with the source gas is supplied.

According to one embodiment of the present disclosure, there is provideda film formation apparatus configured to form a thin film on a substratewithin a vacuum container, including: a rotatable table disposed withinthe vacuum container and configured to revolve a substrate mountingregion on which the substrate is mounted about a rotational center ofthe rotatable table; a first gas supply part configured to supply asource gas of the thin film to a first region through an injectionportion formed to face the rotatable table, the first region beingdefined by partitioning a revolution plane through which the substratemounting region passes, in a direction crossing a revolutional directionof the substrate mounting region; an exhaust part configured to exhausta gas through an exhaust port formed to extend along a first closed pathsurrounding the injection portion; a second gas supply part configuredto supply a separation gas for separating inner and outer sides of asecond closed path from each other through a separation gas supply portformed to extend along the second closed path surrounding the exhaustport; a third gas supply part including two gas injectors arranged toextend at a certain interval in the direction crossing the revolutionaldirection of the substrate mounting regions with a second region definedoutside the second closed path interposed between the two gas injectors,each of the two gas injectors having gas injection holes formed therein,through which a reaction gas reacting with the source gas is suppliedtoward the second region; a plasma generation part for reaction gasconfigured to plasmarize the reaction gas injected toward the secondregion; and other process regions in which processes different from thesupply of the source gas performed by the first gas supply part and thesupply of the reaction gas plasmarized by the plasma generation part areperformed, the other process regions being positioned at locationsdifferent from locations where the first region and the second regionare defined and defined by partitioning the revolution plane throughwhich the substrate mounting region passes in the direction crossing therevolutional direction.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of the specification, illustrate embodiments of the presentdisclosure, and together with the general description given above andthe detailed description of the embodiments given below, serve toexplain the principles of the present disclosure.

FIG. 1 is a longitudinal cross-sectional view of a film formationapparatus according to one embodiment of the present disclosure.

FIG. 2 is a transverse plan view of the film formation apparatus.

FIG. 3 is a top view of the film formation apparatus.

FIG. 4 is an enlarged longitudinal cross-sectional view of a firstregion of the film formation apparatus.

FIG. 5 is a bottom view of a source gas unit disposed in the firstregion of the film formation apparatus.

FIG. 6 is an enlarged longitudinal cross-sectional view of a secondregion of the film formation apparatus.

FIG. 7 is a diagram illustrating a state where a gas injector isdisposed in the second region of the film formation apparatus.

FIG. 8 is a plan view of a slot plate in a plasma generation partdisposed in the second region of the film formation apparatus.

FIG. 9 is an enlarged longitudinal side-sectional view of a pre-reactionregion or a post-reaction region of the film formation apparatus.

FIG. 10 is a diagram illustrating the operation of the film formationapparatus.

FIG. 11 is a diagram illustrating a film thickness distribution in anExample.

FIG. 12 is a diagram illustrating a film thickness distribution inComparative Example 1.

FIG. 13 is another diagram illustrating a film thickness distribution inComparative Example 2.

DETAILED DESCRIPTION

Hereinafter, a film formation apparatus according to one embodiment ofthe present disclosure will be described with reference to FIG. 1 toFIG. 9. In the following detailed description, numerous specific detailsare set forth in order to provide a thorough understanding of thepresent disclosure. However, it will be apparent to one of ordinaryskill in the art that the present disclosure may be practiced withoutthese specific details. In other instances, well-known methods,procedures, systems, and components have not been described in detail soas not to unnecessarily obscure aspects of the various embodiments.

In this embodiment, a silicon nitride (SiN) film is formed on asubstrate by causing a source gas containing dichlorosilane (SiH₂Cl₂) asa precursor to react with a reaction gas containing ammonia (NH₃).

Referring to FIG. 1 and FIG. 2, the film formation apparatus includes: avacuum container 11 defining a process space in which a film formationprocess is carried out; a rotatable table 2 disposed inside the vacuumcontainer 11 and having a plurality of wafer mounting regions 21 formedthereon; a source gas unit 3 configured to supply a source gas toward afirst region R1 in a space defined above the rotatable table 2; a gasinjector 7 (first and second gas injectors 71 and 72) configured tosupply a reaction gas toward a second region R2 partitioned from thefirst region R1; a mechanism configured to supply a pre-process gas anda post-process gas toward a pre-reaction region r1 and a post-reactionregion r2 interposed between the first region R1 and the second regionR2, respectively; and a plasma generation part 6 (referred to sometimesas 6A to 6C) configured to generate plasma of the reaction gas, thepre-process gas, or the post-process gas.

The vacuum container 11 is composed of a container body 13 constitutinga sidewall and a bottom of the vacuum container 11, and a ceiling plate12 for air-tightly sealing an opening formed at an upper side of thecontainer body 13. The vacuum container 11 has a substantially circularflat shape in plan view. The vacuum container 11 (the ceiling plate 12and the container body 13) is formed of, for example, metal such asaluminum, and has an inner surface subjected to a plasma resistancetreatment (for example, an alumite treatment or a thermal spraytreatment of a ceramic material).

The rotatable table 2 disposed inside the vacuum container 11 issubjected to, for example, the same plasma resistance treatment as thatis applied to the vacuum container 11, and is composed of a circularplate formed of a ceramic material. The rotatable table 2 is provided atthe center thereof with a rotational shaft 14 vertically extendingdownward. A rotational driving mechanism 15 such as a motor configuredto rotate the rotatable table 2 around the vertical axis, is installedat a lower end of the rotational shaft 14.

The upper surface of the rotatable table 2 has at least one wafermounting region 21. In this embodiment, as shown in FIG. 1, six wafermounting regions 21 are arranged around a rotational center of therotatable table 2 in the circumferential direction. Each of the wafermounting regions 21 is configured as a circular recess having a slightlygreater diameter than a wafer W.

In addition, the configuration of the wafer mounting regions 21 is notlimited to a simple recess shape which merely receives the wafer W (forexample, see FIG. 7). For example, in addition to the recess, the wafermounting region 21 may have an annular groove formed along the peripheryof the wafer W and having a greater depth than the recess so as toadjust a retention time of the source gas or the reaction gas.

As shown in FIGS. 1, 4 and 6, an annular groove 45 having a flat annularshape is formed in the bottom of the container body 13 disposed belowthe rotatable table 2 in the circumferential direction of the rotatabletable 2. In the annular groove 45, a heater 46 is disposed correspondingto a region in which the wafer mounting regions 21 are arranged. Theheater 46 is to heat the wafers W mounted on the rotatable table 2 up toa temperature suitable for reaction between the source gas and theplasmarized reaction gas. In addition, an opening on an upper surface ofthe annular groove 45 is closed by a heater cover 47 which is an annularplate member. For example, the heater cover 47 is formed of a materialallowing electromagnetic waves radiated from the heater 46 to passtherethrough such that heat radiation from the heater 46 travels towardthe rotatable table 2.

As shown in FIGS. 2 and 3, and the like, an inlet/outlet port 101configured to be opened or closed by a gate valve (not shown) is formedin the sidewall of the vacuum container 11 (container body 13). A waferW held by a transfer mechanism disposed outside the vacuum container 11is carried into the vacuum container 11 through the inlet/outlet port101. Transfer of the wafer W between the transfer mechanism and each ofthe wafer mounting regions 21 is performed by lift pins (not shown)configured to move up and down between an upper location and a lowerlocation of the rotatable table 2 through respective through-holes (notshown) formed in each of the wafer mounting regions 21.

In the rotatable table 2 configured as above, when the rotatable table 2is rotated by the rotational shaft 14, the wafer mounting regions 21revolve about the rotational center C of the rotatable table 2 shown inFIG. 2. Assuming that a region through which the wafer mounting regions21 pass with the rotation of the rotatable table 2 is referred to as arevolution plane R_(A), the revolution plane R_(A) in this embodiment isdefined by an annular region surrounded by a dash-dot line in FIG. 2.

As shown in FIG. 1 and FIG. 4, the source gas unit 3 is disposed on alower surface of the ceiling plate 12 facing the upper surface of therotatable table 2. In addition, as shown in FIG. 2 and FIG. 3, thesource gas unit 3 has a fan shape in plan view, as defined bypartitioning the revolution plane R_(A) of the wafer mounting regions 21in a direction crossing the revolutional direction of the wafer mountingregions 21.

As shown in an enlarged longitudinal cross-sectional view of FIG. 4, forexample, the source gas unit 3 has a structure in which a plurality ofplate members each having a recess or an opening is stacked one aboveanother. As a result, in the inner structure of the source gas unit 3, asource gas diffusion space 33 in which the source gas is diffused, anexhaust space 32 through which the source gas is exhausted, a separationgas diffusion space 31 in which a separation gas for separating a regionunder the source gas unit 3 and a region outside the source gas unit 3is diffused are sequentially stacked from below upward.

The source gas diffusion space 33 formed as the lowermost region of thesource gas unit 3 is coupled to a source gas supply source 52 through aseries of a source gas supply channel 17, an on-off valve V1 and a flowrate regulating part 521. The source gas supply source 52 supplies asource gas containing dichlorosilane.

As shown in FIG. 4 and FIG. 5 which is a bottom view of the source gasunit 3, the source gas diffusion space 33 (the source gas unit 3) isformed in a lower surface thereof with a plurality of injection holes331 through which the source gas is supplied from the source gasdiffusion space 33 toward the rotatable table 2.

As shown in FIG. 5, the injection holes 331 are dispersedly formed in afan-shaped region as indicated by a dotted line of FIG. 5. In thefan-shaped region, the length of two sides extending in the radialdirection of the rotatable table 2 is greater than the diameter of thewafer mounting regions 21 (the wafer W). As a result, when each of thewafer mounting regions 21 passes a region below the source gas unit 3disposed above the revolution plane R_(A) of the respective wafermounting region 21, the source gas is supplied to the entire surface ofthe wafer W mounted inside the wafer mounting region 21 through theinjection holes 331.

The region with the plurality of injection holes 331 formed thereincorresponds to an injection portion 330 of the source gas. In addition,the combination of the injection portion 330, the source gas diffusionspace 33, the source gas supply channel 17, the on-off valve V1, theflow rate regulating part 521, and the source gas supply source 52constitutes a first gas supply part of this embodiment.

As shown in FIG. 4 and FIG. 5, the exhaust space 32 defined above thesource gas diffusion space 33 is in communication with an exhaust port321, which is formed to extend along a closed path (first closed path)surrounding the injection portion 330. In addition, the exhaust space 32is connected to an exhaust device 51 through an exhaust path 192 andforms an independent flow passage through which the source gas suppliedfrom the source gas diffusion space 33 to a region under the source gasunit 3 is exhausted to the exhaust device 51.

The combination of the exhaust port 321, the exhaust space 32, theexhaust path 192, and the exhaust device 51 constitutes an exhaust partof this embodiment.

As shown in FIG. 4 and FIG. 5, the separation gas diffusion space 31defined above the exhaust space 32 is in communication with anseparation gas supply port 311, which is formed to extend along a closedpath (second closed path) surrounding the exhaust port 321. In addition,the separation gas diffusion space 31 is coupled to a separation gassupply source 53 through a series of a separation gas supply channel 16,an on-off valve V2 and a flow rate regulating part 531. The separationgas supply source 53 supplies a separation gas which isolates inner andouter atmospheres of the separation gas supply port 311 from each otherwhile acting as a purge gas for removing the source gas excessivelyadhering to the wafer W. The separation gas may be an inert gas, forexample, a nitrogen gas.

The combination of the separation gas supply port 311, the separationgas diffusion space 31, the separation gas supply channel 16, the on-offvalve V2, the flow rate regulating part 531, and the separation gassupply source 53 constitutes a second gas supply part of thisembodiment.

According to the source gas unit 3 configured as above, the source gassupplied through the injection holes 331 of the injection portion 330spreads toward the periphery side of the upper surface of the rotatabletable 2 while flowing along the upper surface, reaches the exhaust port321 and is finally exhausted from the upper surface of the rotatabletable 2. Accordingly, within the vacuum container 11, a region in whichthe source gas exists is limited inward of the exhaust port 321 formedalong the first closed path (the first region R1).

Further, as described above, the source gas unit 3 has a shape definedby partitioning a portion of the revolution plane R_(A) of the wafermounting region 21 in the direction crossing the revolutional directionof the wafer mounting region 21. Accordingly, when the rotatable table 2is rotated, the wafer W mounted on each of the wafer mounting regions 21passes through the first region R1 so that the source gas can beadsorbed onto the entire surface of the wafer W.

On the other hand, the separation gas supply port 311 is formed aroundthe exhaust port 321 along the second closed path and the separation gasis supplied from the separation gas supply port 311 toward the uppersurface of the rotatable table 2. Accordingly, the inside and theoutside of the first region R1 are separated doubly by the exhaustoperation performed using the exhaust port 321 and the separation gassupplied through the separation gas supply port 311. This configurationsuppresses the source gas from leaking to the outside of the firstregion R1 and suppresses the reaction gas from incoming from the outsideof the first region R1.

The first region R1 may be set to any range without limitation so longas the first region R1 can secure a sufficient contact time for thesource gas to be adsorbed to the entire surface of the wafer W withoutinterfering with the second region R2 defined outside the first regionR1 and to which the reaction gas is supplied. For example, in the casewhere the first region R1 is formed in a fan shape, an angle θ1 definedbetween two sides of the first region R1 extending in the radialdirection of the rotatable table 2 is adjusted to be less than 180degrees at maximum, specifically, to fall within a range of 10 to 110degrees. Further, for the sake of avoiding complexity of descriptions ofFIG. 3, the angle θ1 is shown in FIG. 10.

Using the source gas unit 3 configured as above, the source gas issupplied to the wafer W mounted on each of the wafer mounting regions21, and subsequently, the plasmarized reaction gas generated outside thefirst region R1 is supplied to the wafer W. Thus, the source gasadsorbed to the wafer W reacts with the reaction gas to form a molecularlayer of silicon nitride.

The present inventors found that, in order to form a thin film havinghigh in-plane uniformity in forming a silicon nitride film by depositingthe molecular layers, it is important to form a region where aconcentration of the plasmarized reaction gas is high. In this regard,it is sometimes the case that a method of supplying the reaction gas tothe entire space defined above the rotatable table 2 other than thesource gas unit 3 (the first region R1) fails to form the region wherethe concentration of the reaction gas is high.

Accordingly, in the film formation apparatus according to thisembodiment, two gas injectors 7 (first and second gas injectors 71 and72) are used to form the region where the concentration of the reactiongas is high. The following description will be given of one example of amechanism for supplying the plasmarized reaction gas using the gasinjectors 7.

As shown in FIGS. 2 and 6, and the like, at a downstream side of arotation direction of the rotatable table 2 (in the clockwise directionwhen viewed from the top in this embodiment), the two gas injectors 7(the first and second gas injectors 71 and 72) which extend in theradial direction of the rotatable table 2 (the direction crossing therevolutional direction of the wafer mounting regions 21) are formed inan elongated stick-shape, and are inserted into the vacuum container 11in a mutually spaced-apart relationship along the circumferentialdirection of the rotatable table 2.

Immediately after the wafer W, mounted in the wafer mounting region 21,passes through the first region R1, an excessively-adsorbed source gas(dichlorosilane in this embodiment) may still remain even after purgingthe source gas with the separation gas. Accordingly, as described below,in the film formation apparatus according to this embodiment, apre-process for the wafer W is performed in a region between the firstregion R1 in which the adsorption of the source gas onto the wafer isperformed and the second region R2 in which the supply of theplasmarized reaction gas is performed. To do this, the gas injectors 7are arranged such that the supply of the reaction gas is performed at aplace spaced apart from the downstream side of the first region R1.

In the case of forming the silicon nitride film, each of the gasinjectors 7 is formed of, for example, an elongated ceramic cylindricalmember. The interior of the gas injectors 7 defines a cavity and has aflow passage through which the source gas flows in the longitudinaldirection thereof. In addition, as shown in FIG. 6, a plurality ofreaction gas injection holes 701 is formed at certain intervals in alateral side of each of the gas injectors 7 so as to supply the reactiongas over the entire surface of the wafer W mounted in each of the wafermounting regions 21.

As shown in FIG. 2 and FIG. 6, the gas injectors 7 (the first and secondgas injectors 71 and 72) are arranged such that they are substantiallyhorizontally inserted into the sidewall of the vacuum container 11 (thecontainer body 13) toward the rotational center of the rotatable table 2at an interval of an angle θ2. Like the angle θ1, the angle θ2 is shownin FIG. 10.

The gas injectors 7 are coupled to a reaction gas supply source 54through on-off valves V3 and V4, and flow rate regulating parts 541 and542, respectively. The reaction gas supply source 54 supplies an ammonia(NH₃)-containing reaction gas. The combination of the gas injectors 7(the first and second gas injectors 71 and 72), the on-off valves V3 andV4, the flow rate regulating parts 541 and 542, and the reaction gassupply source 54 constitutes a third gas supply part of this embodiment.

As schematically shown in FIG. 7, the first and second gas injectors 71and 72 are arranged such that the reaction gas injection holes 701formed in one injector face those formed in another injector. Thus, thereaction gas can be supplied toward a plasma generation region P inwhich the plasmarized reaction gas is generated by an antenna part 60for generating plasma (to be described below). The range of the plasmageneration region P varies depending upon conditions such as an internalpressure of the vacuum container 11, the kind, concentration or flowrate of the source gas, or the like.

Conversely, the arrangement height of the first and second gas injectors71 and 72, the range in which the reaction gas injection holes 701 areformed along the longitudinal direction of the first and second gasinjectors 71 and 72, the orientation of the reaction gas injection holes701 and the like are set such that the source gas can be injected towardthe plasma generation region P, based on a promise that variousconditions are determined depending upon a range in which the plasmageneration region P is formed. The formation range of the plasmageneration region P can be confirmed by a plasma light emission area.

In addition, if the gas injectors 7 are arranged inside the plasmageneration region P, the reaction gas starts to be plasmarized insidethe gas injectors 7, which may deteriorate activity of the plasma of thesource gas injected from the reaction gas injection holes 701.Accordingly, as shown in FIG. 7, the gas injectors 7 (the first andsecond gas injectors 71 and 72) are arranged near the plasma generationregion P.

As described above, it is possible to form the region where theconcentration of the reaction gas is high by using the two gas injectors7 (the first and second gas injectors 71 and 72) arranged to inject thereaction gas toward a certain region through the reaction gas injectionholes 701, in a state where the certain region defined outside the firstregion R1 to which the source gas is supplied is interposed between thetwo gas injectors 7.

In view of forming the region where the concentration of the reactiongas is high, the angle θ2 defined between the two gas injectors 7 (thefirst and second gas injectors 71 and 72) may be adjusted to be lessthan 180 degrees, specifically, in a range of 10 to 110 degrees.

Furthermore, as shown in FIG. 6, in the film formation apparatusaccording to this embodiment, peripheral-side reaction gas injectionholes 702 are formed to supply the reaction gas from a position, whichcorresponds to a peripheral side of the rotatable table 2, toward theregion defined between the two gas injectors 7 (the first and second gasinjectors 71 and 72). For example, the peripheral-side reaction gasinjection holes 702 are formed in an inner peripheral surface of theceiling plate 12 having an opening portion formed therein, whichsupports a dielectric window 61. Thus, the reaction gas is suppliedtoward a region under the dielectric window 61 formed in the antennapart 60 (to be described later).

The peripheral-side reaction gas injection holes 702 are arranged atcertain intervals along one side of the periphery of the rotatable table2 in the second region R2 defined between the two gas injectors 7 (thefirst and second gas injectors 71 and 72) and having a triangular shapein a plan view. As a result, as schematically indicated by solid linesin the second region R2 shown in FIG. 10, the reaction gas can beinjected from the one side of the periphery of the rotatable table 2 inthe direction crossing the revolutional direction of the wafer mountingregions 21 through the peripheral-side reaction gas injection holes 702.

As shown in FIG. 6, each of the peripheral-side reaction gas injectionholes 702 is in communication with a reaction gas supply channel 183formed to extend along one side of the inner peripheral surface of theceiling plate 12. The reaction gas supply channel 183 is coupled to thereaction gas supply source 54 through an on-off valve V5 and a flow rateregulating part 543 disposed outside the ceiling plate 12. By formingthe peripheral-side reaction gas injection holes 702, it is possible tosupply the reaction gas toward the region to which the reaction gas issupplied from the two gas injectors 7 described above, thereby furtherincreasing the concentration of the reaction gas in the respectiveregion. The combination of the reaction gas supply channel 183, theperipheral-side reaction gas injection holes 702, the on-off valve V5,the flow rate regulating part 543, and the reaction gas supply source 54constitutes a fourth gas supply part of this embodiment. In FIG. 1, theperipheral-side reaction gas injection holes 702 and the reaction gassupply channel 183 and the like are omitted for the sake of simplicity.

Further, the supply of the reaction gas from the fourth gas supply partis not essential. For example, the fourth gas supply part may be omittedas long as a high concentration of the reaction gas can be sufficientlysupplied from the gas injectors 7 (the first and second gas injectors 71and 72) toward the region around the periphery of the rotatable table 2.

Next, the plasma generation part 6 (6A) configured to plasmarize thereaction gas supplied from the aforementioned gas injectors 7 will bedescribed.

As shown in FIG. 3 and FIG. 6, the plasma generation part 6 (6A)includes the antenna part 60 configured to radiate microwaves toward theinterior of the vacuum container 11, a coaxial waveguide 65 configuredto supply microwaves toward the antenna part 60, and a microwavegenerator 69. The antenna part 60 is installed in the ceiling plate 12disposed above the region to which the reaction gas is supplied from thegas injectors 7 (the first and second gas injectors 71 and 72). Theantenna part 60 closes a substantially triangular opening portion formedin the ceiling plate 12, which corresponds to the region.

The antenna part 60 is configured as a radial line slot antenna (RLSA®,Tokyo Electron Kabushiki Kaisha)) including the dielectric window 61, aslot plate 62, a dielectric plate 63, and a cooling jacket 64.

The dielectric window 61 is to reduce wavelength of microwaves and isformed of, for example, alumina ceramic. The dielectric window 61 has asubstantially triangular shape capable of closing the opening portion ofthe ceiling plate 12 when viewed from the top. The periphery of thedielectric window 61 is supported by a member around the opening portionformed in the ceiling plate 12. A region inward of the periphery of thedielectric window 61 is exposed toward the interior of the vacuumcontainer 11. In some embodiments, an annular recess 611 having atapered surface may be formed in a lower surface of the dielectricwindow 61 so as to stably generate plasma by concentrating energy of themicrowaves on a certain region.

The slot plate 62 is configured as a substantially triangular metalplate with a plurality of slot holes 621 formed therein. As shown as oneexample in the plan view of FIG. 8, the plurality of slot holes 621formed in the slot plate 62 is arranged at certain intervals in adiametric direction oriented from the center of the triangular shape tothe periphery thereof and along a circumferential direction. Further,each of the slot holes 621 is formed such that adjacent slot holes 621and 621 are oriented to intersect each other or in a directionorthogonal to each other.

Further, the dielectric plate 63 is disposed on the slot plate 62. Thedielectric plate 63 is formed of, for example, alumina ceramic, and hasa substantially triangular shape corresponding to the shape of thedielectric window 61 or the slot plate 62 in plan view. The coolingjacket 64 is disposed on the dielectric plate 63. The cooling jacket 64includes a coolant channel 641 formed therein. The antenna part 60 canbe cooled down by causing a coolant to flow through the coolant channel641.

The antenna part 60 is coupled to the microwave generator 69 through thecoaxial waveguide 65, a mode convertor 66, and a waveguide 67. Thecoaxial waveguide 65 includes a substantially cylindrical innerconductor 651 and a substantially cylindrical outer conductor 652. Alower end portion of the inner conductor 651 is connected to thedielectric plate 63 and an upper end thereof is connected to the modeconvertor 66. A lower end portion of the outer conductor 652 isconnected to an upper surface of the cooling jacket 64 which is formedof, for example, a metal (conductive) material. An upper end portion ofthe outer conductor 652 is connected to the mode convertor 66. The innerconductor 651 is received in the outer conductor 652.

The microwave generator 69 generates microwaves having a frequency of,for example, 2.45 GHz. The microwaves generated by the microwavegenerator 69 is introduced into the coaxial waveguide 65 through a tuner68 used as a matching device, the waveguide 67, and the mode convertor66 which converts the microwaves into a propagation mode adapted to flowthrough the coaxial waveguide 65.

In the plasma generation part 6 configured as above, the microwavesgenerated by the microwave generator 69 are supplied to the dielectricplate 63 through the coaxial waveguide 65, and then supplied to a spaceunder the dielectric window 61 through the slot holes 621 of the slotplate 62.

As described above, in the plasma generation part 6, the planar shape ofthe antenna part 60 is a substantially triangular shape corresponding tothe fan shape of the region to which the reaction gas is supplied fromthe two gas injectors 7 (the first and second gas injectors 71 and 72).Accordingly, the region in which the reaction gas is plasmarized has ashape corresponding to the shape of the antenna part 60 (the planarshape of the dielectric window 61 exposed to the interior of the vacuumcontainer 11).

In the film formation apparatus according to this embodiment, theaforementioned region in which the reaction gas is plasmarized is set asthe second region R2.

Accordingly, the gas injectors 7 (the first and second gas injectors 71and 72) may be said to be arranged with the second region R2 interposedbetween the gas injectors 7. Furthermore, the plasma generation part 6may be said to have a configuration in which the reaction gas injectedtoward the second region R2 is plasmarized. In addition, as describedabove, the gas injectors 7 are arranged to extend in the directioncrossing the revolutional direction of the wafer mounting regions 21.The reaction gas injection holes 701 are formed over the range in whichthe reaction gas can be supplied toward the entire surface of the waferW. Accordingly, with the rotation of the rotatable table 2, the wafer Wmounted in each of the wafer mounting regions 21 passes through thesecond region R2 where the plasmarized reaction gas can be supplied tothe entire surface of the wafer W to which the source gas is adsorbed.

As shown in FIG. 2 and FIG. 6, an exhaust groove 191 is formed outwardof the region in which the second region R2 is formed to exhaust thereaction gas. The exhaust groove 191 is formed in a bottom surface sidebetween the rotatable table 2 and an inner wall surface of the vacuumcontainer 11 in the container body 13 along the circumferentialdirection of the rotatable table 2. An exhaust port 190A is formed in abottom portion of the exhaust groove 191. The exhaust port 190A iscoupled to an exhaust device 51 configured to evacuate the interior ofthe vacuum container 11 through an exhaust channel 19.

The combination of the exhaust groove 191, the exhaust port 190A, theexhaust channel 19 and the exhaust device 51 constitutes a reaction gasexhaust part of this embodiment. In some embodiments, for example, arectifying plate having a plurality of orifices formed therein may beinstalled above the exhaust groove 191 such that the exhaust isuniformly performed outward of the second region R2.

The film formation apparatus according to this embodiment and having theconfiguration as described above may perform a process different fromthe supply of the source gas or the plasmarized reaction gas in a regiondifferent from the first and second regions R1 and R2.

In the film formation apparatus according to this embodiment, examplesof the process performed in the different region may include apre-process in which impurities contained in the source gas adsorbed tothe wafer W is removed and a post-process in which a film is densified(modified) by coupling dangling bonds of a thin film formed on the waferW.

As shown in FIG. 2, the pre-reaction region r1 is defined at adownstream side of the first region R1 and at an upstream side of thesecond region R2 when viewed in the revolutional direction of the wafermounting regions 21 (in the rotational direction of the rotatable table2). Further, the planar shape of the pre-reaction region r1 is asubstantially triangular shape defined by partitioning the revolutionplane R_(A) through which the wafer mounting regions 21 pass, in thedirection crossing the revolutional direction of the wafer mountingregions 21.

On the other hand, the post-reaction region r2 is defined at adownstream side of the second region R2 and at an upstream side of thefirst region R1 when viewed in the revolutional direction. Further, theplanar shape of the post-reaction region r2 is a substantiallytriangular shape defined by partitioning the revolution plane R_(A)through which the wafer mounting regions 21 pass, in the directioncrossing the revolutional direction of the wafer mounting regions 21.

The pre-reaction region r1 and the post-reaction region r2 share acommon configuration except that there is a case where components ofgases supplied to the wafer W are different from each other. In thisregard, the configuration of the pre-reaction region r1 will be firstdescribed with reference to FIG. 9 which is a common enlargedlongitudinal side view. As shown in FIG. 9, the pre-reaction region r1is formed with peripheral-side process gas injection holes 703 andcentral-side process gas injection holes 704 through which a pre-processgas is supplied to the pre-reaction region r1.

The peripheral-side process gas injection holes 703 are formed in aninner peripheral surface of the ceiling plate 12 having an openingportion formed therein, which supports the dielectric window 61, suchthat various kinds of process gases are supplied toward a region underthe dielectric window 61 installed in the antenna part 60 of the plasmageneration part 6 (or 6B) to be described below. The peripheral-sideprocess gas injection holes 703 are arranged at plural places in amutually spaced-apart relationship along one side of the periphery ofthe rotatable table 2 in the pre-reaction region r1 whose planar shapeis a substantially triangular shape.

Each of the peripheral-side process gas injection holes 703 is incommunication with a peripheral-side gas supply channel 184 formed toextend along one side of the periphery of the pre-reaction region r1.The peripheral-side gas supply channel 184 is coupled to a pre-processgas supply source 55 through an on-off valve V61 and a flow rateregulating part 551 disposed outside the ceiling plate 12.

On the other hand, the central-side process gas injection holes 704 arearranged at plural places (e.g., two places) in a mutually spaced-apartrelationship along a vertex side of the pre-reaction region r1 having asubstantially triangular shape, which faces the inner peripheral surfacein which the peripheral-side process gas injection holes 703 are formed.

Each of the central-side process gas injection holes 704 is incommunication with a common central-side process gas supply channel 185formed at the vertex side of the pre-reaction region r1. Thecentral-side process gas supply channel 185 is coupled to thepre-process gas supply source 55 through an on-off valve V71 and a flowrate regulating part 552 disposed outside the ceiling plate 12.

The pre-process gas supply source 55 supplies the pre-process gascontaining hydrogen to remove chlorine as impurities contained in thesource gas adhering to the wafer W. Instead of hydrogen, gas as anitrogen source such as ammonia or nitrogen or gas as a radical sourcesuch as argon may be added to the pre-process gas.

In the pre-reaction region r1, the combination of the peripheral-sideprocess gas injection holes 703, the peripheral-side gas supply channel184, the on-off valve V61, the flow rate regulating part 551, thecentral-side process gas injection holes 704, the on-off valve V71, theflow rate regulating part 552, and the pre-process gas supply source 55constitutes a pre-process gas supply part of this embodiment.

With the configuration as described above, as schematically indicated bysolid lines in the pre-reaction region r1 of FIG. 10, it is possible toinject the pre-process gas from the peripheral-side process gasinjection holes 703 formed at the one side of the periphery of thepre-reaction region r1 and the central-side process gas injection holes704 formed at the vertex side of the pre-reaction region r1 which facesthe one side of the periphery, in the direction crossing therevolutional direction of the wafer mounting regions 21.

Further, when viewed in the revolutional direction of the wafer mountingregions 21, the exhaust groove 191 having an exhaust port 190B formedtherein is formed in a bottom surface of the container body 13 betweenthe rotatable table 2 and the inner wall surface of the vacuum container11 at the upstream side of the pre-reaction region r1, so as todischarge the pre-process gas outside of the vacuum container 11. Theformation of the exhaust port 190B at the upstream side of thepre-reaction region r1 causes the pre-process gas supplied to thepre-reaction region r1 to flow in a direction away from the secondregion R2 (FIG. 10).

In addition, as shown in FIGS. 3 and 6, and the like, the pre-reactionregion r1 is provided with the plasma generation part 6 (6B) configuredto plasmarize the pre-process gas. The plasma generation part 6 (6B) issimilar in configuration to the plasma generation part 6 (or 6A)configured to plasmarize the reaction gas in the second region R2 sideas described above with reference to FIG. 6, and thus a repeateddescription thereof will be omitted.

Next, the post-reaction region r2 will be described with a focus on thedifferences from the pre-reaction region r1. Similar to the pre-reactionregion r1, even in the post-reaction region r2 whose planar shape is asubstantially triangular shape, the peripheral-side process gasinjection holes 703 are arranged at plural places along one side of theperiphery of the rotatable table 2. The peripheral-side process gasinjection holes 703 are coupled to a post-process gas supply source 56through the peripheral-side gas supply channel 184, an on-off valve V62and a flow rate regulating part 561. Further, similar to thepre-reaction region r1, even in the post-reaction region r2, thecentral-side process gas injection holes 704 are arranged at pluralplaces along a vertex side of the substantially triangular shape whichfaces the one side of the periphery. The central-side process gasinjection holes 704 are coupled to the post-process gas supply source 56through the central-side process gas supply channel 185, an on-off valveV72, and a flow rate regulating part 562.

The post-process gas supply source 56 supplies a post-process gascontaining a hydrogen gas to densify (modify) a thin film by couplingdangling bonds in the thin film formed on the wafer W. In thepost-reaction region r2, the combination of the peripheral-side processgas injection holes 703, the peripheral-side gas supply channel 184, theon-off valve V62, the flow rate regulating part 561, the central-sideprocess gas injection holes 704, the on-off valve V72, the flow rateregulating part 562, and the post-process gas supply source 56constitutes a post-process gas supply part of this embodiment.

With the configuration as described above, as schematically indicated bysolid lines in the post-reaction region r2 of FIG. 10, it is possible toinject the post-process gas from the peripheral-side process gasinjection holes 703 formed at the one side of the periphery of thepost-reaction region r2 and the central-side process gas injection holes704 formed at the vertex side of the post-reaction region r2 which facesthe one side of the periphery, in the direction crossing therevolutional direction of the wafer mounting regions 21.

Even in the post-reaction region r2, an exhaust port 190C for thepost-process gas is formed at a downstream side of the post-reactionregion r2. The formation of the exhaust port 190C at the downstream sideof the post-reaction region r2 causes the post-process gas supplied tothe post-reaction region r2 to flow in a direction away from the secondregion R2 (FIG. 10).

In addition, the plasma generation part 6 (or 6C) configured toplasmarize the post-process gas is installed in the post-reaction regionr2. The plasma generation part 6 (or 6C) is similar in configuration tothe plasma generation part 6 (or 6A) configured to plasmarize thereaction gas in the second region R2 side as described above withreference to FIG. 6, and thus a repeated description thereof will beomitted.

As shown in FIG. 1, the film formation apparatus is provided with acontrol part 8. The control part 8 is composed of a computer including acentral processing unit (CPU) (not shown) and a memory (not shown). Thememory stores a program including steps (commands) for outputtingcontrol signals to execute respective operations of the rotatable table2, the first to fourth gas supply parts, the pre-process gas supplypart, the post-process gas supply part, and the plasma generation part 6(6A to 6C). The program may be stored in a storage medium, for example,a hard disk, a compact disk, a magnetic-optical disk, a memory card, andthe like, and may be installed in the memory from the storage medium.

Next, the operation of the film formation apparatus according to thisembodiment which is configured as above, will be described.

First, the gate valve of the inlet/outlet port 101 is opened and thewafer W is carried into the vacuum container 11 by an external transfermechanism. Thereafter, the wafer W is delivered to the respective wafermounting region 21 of the rotatable table 2 using lift pins (not shown).Such a delivery of the wafer W is performed while intermittentlyrotating the rotatable table 2 so that all the wafers W are mounted onthe respective wafer mounting regions 21.

Then, the transfer mechanism is retracted from the vacuum container 11and the gate valve of the inlet/outlet port 101 is closed. At this time,the interior of the vacuum container 11 is evaluated to a predeterminedpressure by the exhaust device 51. Further, a separation gas is suppliedfrom the separation gas supply port 311.

Thereafter, while rotating the rotatable table 2 clockwise at a presetrotational speed, each of the wafers W is heated by the heater 46. Uponconfirming that the temperature of the wafers W reaches a presettemperature using a temperature sensor (not shown), the supply of thesource gas from the injection portion 330, the supply of the reactiongas from the gas injectors 7 (the first and second gas injectors 71 and72) and the peripheral-side reaction gas injection holes 702, and thesupply of the pre-process gas and the post-process gas from theperipheral-side process gas injection holes 703 and the central-sideprocess gas injection holes 704 formed in the pre-reaction region r1 andthe post-reaction region r2 are initiated, respectively. Further, inparallel with the initiation of the supply of the reaction gas and thelike, microwaves are supplied from the antenna part 60 of the plasmageneration parts 6 (6A to 6C) for the reaction gas, the pre-process gasand the post-process gas.

As a result, as shown in FIG. 10, in the vacuum container 11, the sourcegas supplied from the injection portion 330 of the source gas unit 3flows through the interior of the first region R1 which is a restrictedspace including the exhaust space 32 that surrounds the injectionportion 330. Further, the reaction gas, which is supplied from the gasinjectors 7 (the first and second gas injectors 71 and 72) and theperipheral-side reaction gas injection holes 702, followed by beingplasmarized by the microwaves, followed by being discharged to theexhaust port 190A of the exhaust groove 191, flows at a highconcentration in the second region R2. In addition, the wafer mountingregions 21 of the rotatable table 2 and the wafers W are omitted in FIG.10.

When the source gas is supplied to the first region R1 and theplasmarized reaction gas is supplied to the second region R2, the waferW mounted on each of the wafer mounting regions 21 alternately passesthrough the first region R1 and the second region R2. As a result,dichlorosilane of the source gas is adsorbed onto the surface of thewafer W and subsequently, reacts with ammonia in the plasmarizedreaction gas, thus forming a molecular layer of silicon nitride on thesurface of the wafer W. In this way, the molecular layers of siliconnitride are sequentially laminated to form a thin film of siliconnitride.

In the operation described above, by supplying the reaction gas to thesecond region R2, it is possible to supply the plasmarized reaction gasto the wafer W with high concentration, as compared with the case wherethe reaction gas is supplied to the entire interior of the vacuumcontainer 11 excluding the first region R1. As a result, as described inthe following examples, it is possible to improve in-plane uniformity inthickness of the film formed on the wafer W.

In some embodiments, the flow rate of the reaction gas supplied from thefirst gas injector 71 disposed at the upstream side in the rotationaldirection of the rotatable table 2 may be the same as or different thanthe flow rate of the reaction gas supplied from the second gas injector72 disposed at the downstream side in the rotational direction of therotatable table 2.

For example, after a film is formed on the wafer W, a thicknessdistribution of the film formed on the wafer W was measured. Thismeasurement shows that, when viewed in the rotational direction of therotatable table 2, the film formed on an end portion (upstream endportion) of the wafer W initially entering the second region R2 has arelatively thin thickness, and the film formed on the other end portion(downstream end portion) of the wafer W subsequently entering the secondregion R2 has a relatively thick thickness. In this case, it can be seenthat the flow rate of the reaction gas is regulated such that, forexample, the flow rate of the reaction gas supplied from the first gasinjector 71 disposed at the upstream side becomes higher than the flowrate of the reaction gas supplied from the second gas injector 72disposed at the downstream side, thus planarizing the aforementionedfilm thickness distribution.

In the film formation apparatus according to this embodiment, an innerspace of the vacuum container 11 other than the first region R1 doublyseparated by the exhaust operation performed through the exhaust port321 and the separation gas is divided into the second region R2 and theremaining region by the flow of the reaction gas.

As a result, it is possible to form the pre-reaction region r1 at thedownstream side of the first region R1 and at the upstream side of thesecond region R2. The plasmarized pre-process gas is supplied toward thepre-reaction region r1 so that chlorine as impurities contained in thesource gas adsorbed onto the wafer in the first region R1 are removed,which makes it possible to improve quality of the film formed on thewafer W.

Further, it is possible to form the post-reaction region r2 at thedownstream side of the second region R2 and at the upstream side of thefirst region R1. The plasmarized post-process gas is supplied toward thepost-reaction region r2 to couple dangling bonds in the thin film formedon the wafer W, which makes it possible to densify the film.

Here, in the case where the rotatable table 2 rotates once, a procedurefrom when supplying the source gas to be adsorbed onto the wafer Wmounted on each of the wafer mounting regions 21 in the first region R1and causing the source gas to react with the plasmarized reaction gas inthe second region R2 to form a molecular layer of silicon nitride, untilimmediately before further supplying the source gas to be adsorbed ontothe wafer in the first region R1, is referred as to one cycle.

The pre-reaction region r1 and the post-reaction region r2 are disposedbetween the first region R1 and the second region R2. Thus, theaforementioned pre-process and post-process can be carried out duringone cycle. As a result, it is possible to reliably performing theaforementioned pre-process and post-process with respect to eachmolecular layer in the course of depositing the silicon nitride to formthe thin film.

In addition, as shown in FIG. 10, the exhaust ports 190B and 190C areformed such that the pre-process gas supplied in the pre-reaction regionr1 and the post-process gas supplied in the post-reaction region r2 flowin a direction away from the second region R2. Thus, it is possible toreliably separate the reaction gas supplied to the second region R2 fromthe pre-process gas and the post-process gas in the single vacuumcontainer 11.

If the thin film of silicon nitride having a desired thickness is formedby performing the above operation for a predetermined period of time,the supply of the source gas and the reaction gas and the heating of thewafer W by the heater 46 are stopped. Further, if the temperature of thewafer W is decreased up to a preset temperature, the wafers W aresequentially unloaded from the vacuum container 11 through theinlet/outlet port 101 in a reverse order of the loading operation asdescribed above, and the film formation operation is terminated.

The film formation apparatus according to this embodiment provides thefollowing effects. The two gas injectors 7 (the first and second gasinjectors 71 and 72) are disposed in an inner region of the vacuumcontainer 11 separated from the first region R1 to which the source gasis supplied, with the second region R2 to which the plasmarized reactiongas is supplied interposed between the two gas injectors 7. Thus, thespace through which the wafer mounting regions 21 formed on therotatable table 2 pass in the interior of the vacuum container 11 isfurther divided. Further, in a space between the first region R1 and thesecond region R2, the pre-reaction region r1 in which the pre-processfor removing impurities contained in the source gas adsorbed onto thewafer W is performed, and the post-reaction region r2 in which thepost-process for coupling dangling bonds of the thin film formed on thewafer W to densify the thin film is performed, is formed. Thepre-process and the post-process are different from the process ofsupplying the source gas and the plasmarized reaction gas. As a result,it is possible to perform another process required to improve a filmquality after the film formation, in a film formation cycle in which theadsorption of the source gas to the wafer W and the reaction of thesource gas with the reaction gas are alternately repeated.

Examples of the process different from the supply of the source gas inthe first region R1 and the supply of the plasmarized reaction gas inthe second region R2 is not limited to the pre-process for removingimpurities contained in the source gas adsorbed onto the wafer W and thepost-process for coupling dangling bonds of the thin film formed on thewafer W to densify the thin film.

For example, a process of supplying an H₂ gas to modify a formed SiO₂film may be performed. Further, it is not essential that a plasmageneration part configured to plasmarize a process gas is installed inthe region in which another process is performed. For example, the otherprocess may include a remote plasma process of introducing a process gasplasmarized outside the vacuum container 11 into another process region,or a process of causing the thin film to react with a process gas byheating the thin film using the heater 46.

Further, it is not essential that the two gas injectors 7 (the first andsecond gas injectors 71 and 72) are radially arranged toward therotational center of the rotatable table 2, as shown in FIG. 2 and thelike. For example, the two gas injectors 7 (the first and second gasinjectors 71 and 72) may be arranged in a mutually parallel relationshipwhen viewed from the top, with the two gas injectors 7 positioned in thedirection crossing the revolutional direction of the wafer mountingregions 21. In this case, when viewed from the top the first and secondgas injectors 71 and 72 which are arranged (in a concentricrelationship) at locations separated from the rotational center of therotatable table 2 by the same distance in the radial direction, an anglebetween the two gas injectors 7 (the first and second gas injectors 71and 72) may be greater than 0 degrees and less than 180 degrees asdescribed above. This concept can be applied to the case where the firstand second gas injectors 71 and 72 have a curved shape instead of alinear stick shape.

Further, even in the case where the first region R1 does not have a fanshape, an angle defined between two sides extending in the directioncrossing the revolutional direction of the wafer mounting regions 21 maybe defined as in the definition of the angle between the gas injectors7.

Furthermore, the number of the gas injectors 7 used in forming thesecond region R2 is not limited to the example in which a single firstgas injector 71 is disposed at the upstream side and a single second gasinjector 72 is disposed at the downstream side. For example, two or moreof the first and second gas injectors 71 and 72 may be verticallyarranged one above another, respectively. Even in this case, a pluralset of the first and second gas injectors 71 and 72 may be arranged withthe second region R2 interposed between the respective first and secondgas injectors 71 and 72, and an angle defined between two first andsecond gas injectors 71 and 72 in each set may be set to be less than180 degrees.

Furthermore, the configuration of the injection portion 330 forsupplying the source gas to the first region R1 is not limited to anexample of a porous plate having the plurality of injection holes 331formed therein as shown in FIG. 5. For example, a reversed bowl-shapedrecess whose height is gradually increased from the periphery toward thecenter may be formed inside the exhaust port 321, and a source gas maybe injected from a single gas nozzle installed at an upper end positionof the recess.

Methods other than RLSA may be employed instead of the method ofplasmarizing the reaction gas. For example, a coil-shaped antenna may bedisposed at the upper surface side of the ceiling plate 12 and plasmamay be generated by an inductive coupling.

In addition, the kind of thin film formed by the film formationapparatus according to this embodiment is not limited to siliconnitride. For example, a thin film of silicon oxide (SiO₂) may be formedby supplying a BTBAS (bistertiarybutylaminosilane) gas as the source gasand an oxygen (O₂) gas as the reaction gas to be plasmarized. In thiscase, quartz may be used as a material of the gas injectors 7.

EXAMPLE Experiment

An experiment was performed to measure a film thickness distribution anddensity of a silicon nitride film formed on a wafer W using the filmformation apparatus according to the present embodiment and aconventional film formation apparatus which supplies a reaction gaswithout having to use the gas injectors 7.

A. Experimental Conditions Example

The silicon nitride film was formed using the film formation apparatusdescribed with reference to FIG. 1 to FIG. 10. A flow rate of a sourcegas (in a concentration of 100 vol % for dichlorosilane) supplied to thefirst region R1 was set to 1,000 ccm. Flow rates of reaction gases (in aconcentration of 100 vol % for ammonia and 100 vol % for argon) were setto 800 ccm for ammonia and 5,000 ccm for argon. A heating temperature ofthe wafer W was set to 475 degrees C. Further, hydrogen was supplied asa pre-process gas at a flow rate of 4,000 ccm to the pre-reaction regionr1 and was also supplied as a post-process gas at a flow rate of 4,000ccm to the post-reaction region r2. A rotational speed of the rotatabletable 2 was set to 20 rpm. A film formation process was performed whilethe rotatable table 2 rotates a total of 87 times. The film thicknessdistribution of the silicon nitride film thus formed was measured usinga film thickness meter. Further, as an index indicating the density ofthe silicon nitride film, a wet etching rate (WER, [Å/min]) was measuredusing fluoric acid having a concentration of 0.5 wt % by weight.

Comparative Example 1

In the film formation apparatus described with reference to FIG. 10,reaction gases (in a concentration of 100 vol % for ammonia, 100 vol %for hydrogen) were supplied from the peripheral-side process gasinjection holes 703 and the central-side process gas injection holes 704described with respect to FIG. 9 to the region in which the plasmageneration parts 6 (6A to 6C) are disposed, without having to use thegas injectors 7 (the first and second gas injectors 71 and 72). A sourcegas (in a concentration of 100 vol % for dichlorosilane) was supplied ata flow rate of 1,000 ccm and the heating temperature of the wafer W wasset to 475 degrees C. The rotational speed of the rotatable table 2 wasset to 20 rpm. At this time, a film formation process was performedduring the rotatable table 2 rotates a total of 87 times. A filmthickness distribution and WER of a silicon nitride film formed on thewafer were measured in the same manner as that in the above Example.

Comparative Example 2

A film formation process of Comparative Example 2 was performed underthe same conditions as those in Comparative Example 1 except that, afterthe silicon nitride film is formed, hydrogen as a post-process gas wassupplied at a flow rate of 4,000 ccm to the region in which the plasmageneration parts 6 (6A to 6C) are disposed. A film thicknessdistribution and WER of the silicon nitride film formed on the waferwere measured in the same manner as that in the above Example.

B. Experimental Result

Measurement results of the film thickness distribution of the aboveExample are shown in FIG. 11 and measurement results of the filmthickness distribution of Comparative Examples 1 and 2 are shown in FIG.12 and FIG. 13. According to the measurement results of the Example andComparative Examples 1 and 2, the silicon nitride film of the Examplewas relatively uniform in in-plane film thickness of the wafer W,whereas the silicon nitride films of Comparative Examples 1 and 2exhibited a significant tendency to gradually increase in the filmthickness from a location at the center side of the rotatable table 2toward the center of the wafer W. In terms of a ratio of ±3σ (Å) to anaverage film thickness (Å), the silicon nitride film of the Example was1.6%, the silicon nitride film of Comparative Example 1 was 19.5%, andthe silicon nitride film of Comparative Example 2 was 32.0%.Accordingly, it could be confirmed that the film formation apparatusaccording to this embodiment has an effect of significantly improvingin-plane uniformity of the thin film formed on the wafer W.

For film density, WER of the silicon nitride film of the Example was11.4 [Å/min]. Conversely, in Comparative Example 2 in which thepost-process using hydrogen is additionally performed after the filmformation process, WER was 9.0 [Å/min]. The present inventors aimed todevelop a film formation apparatus capable of forming a dense siliconnitride film having WER of about 10±1 [Å/min]. Accordingly, it can besaid that a film quality of the silicon nitride film formed in theExample is substantially identical to that in the case (ComparativeExample 2) where the post-process is additionally performed after thefilm formation process. On the other hand, in the Example, it can beevaluated that, since a time period of the post-process performed afterthe film formation process was reduced, a process efficiency of the filmformation apparatus was significantly improved. Furthermore, WER inComparative Example 1 in which the hydrogen-based post-process is notperformed was 16.9 [Å/min]. Thus, it can be evaluated that a filmquality in Comparative Example 1 was degraded as compared with theExample.

According to the present disclosure in some embodiments, two gasinjectors are arranged, inside a vacuum container, in a region separatedfrom a first region to which a source gas is supplied, in such a mannerthat a second region to which a plasmarized reaction gas is suppliedinterposed between the two gas injectors. Thus, the inner space of thevacuum container through which substrate mounting regions formed on arotatable table pass is further divided. Further, other process regionsin which different processes different from the supply of the source gasor the supply of the plasmarized reaction gas are performed, are formedbetween the first region and the second region. As a result, it ispossible to perform another process required after a film formationprocess during a film formation cycle in which a process of adsorbingthe source gas onto the substrate and a process of causing the sourcegas to react with the reaction gas are alternately repeated.

While certain embodiments have been described, these embodiments havebeen presented by way of example only, and are not intended to limit thescope of the disclosures. Indeed, the embodiments described herein maybe embodied in a variety of other forms. Furthermore, various omissions,substitutions and changes in the form of the embodiments describedherein may be made without departing from the spirit of the disclosures.The accompanying claims and their equivalents are intended to cover suchforms or modifications as would fall within the scope and spirit of thedisclosures.

What is claimed is:
 1. A film formation apparatus configured to form athin film on a substrate within a vacuum container, comprising: arotatable table disposed within the vacuum container and configured torevolve a substrate mounting region on which the substrate is mountedabout a rotational center of the rotatable table; a first gas supplypart configured to supply a source gas of the thin film to a firstregion through an injection portion formed to face the rotatable table,the first region being defined by partitioning a revolution planethrough which the substrate mounting region passes, in a directioncrossing a revolutional direction of the substrate mounting region; anexhaust part configured to exhaust a gas through an exhaust port formedto extend along a first closed path surrounding the injection portion; asecond gas supply part configured to supply a separation gas forseparating inner and outer sides of a second closed path from each otherthrough a separation gas supply port formed to extend along the secondclosed path surrounding the exhaust port; a third gas supply partincluding two gas injectors arranged to extend at a certain interval inthe direction crossing the revolutional direction of the substratemounting regions with a second region defined outside the second closedpath interposed between the two gas injectors, each of the two gasinjectors having gas injection holes formed therein, through which areaction gas reacting with the source gas is supplied toward the secondregion, wherein the two gas injectors are arranged such that the gasinjection holes formed in one gas injector face the injection holesformed in the other gas injector; a plasma generation part for reactiongas configured to plasmarize the reaction gas injected toward the secondregion; and other process regions in which processes different from thesupply of the source gas performed by the first gas supply part and thesupply of the reaction gas plasmarized by the plasma generation part areperformed, the other process regions being positioned at locationsdifferent from locations where the first region and the second regionare defined and defined by partitioning the revolution plane throughwhich the substrate mounting region passes in the direction crossing therevolutional direction, wherein the other process regions include apre-reaction region defined at a downstream side of the first region andat an upstream side of the second region when viewed in the revolutionaldirection of the substrate mounting region; and a pre-process gas supplypart installed in the pre-reaction region and configured to supply apre-process gas for removing impurities contained in the source gas thatis adsorbed onto the substrate in the first region.
 2. The filmformation apparatus of claim 1, further comprising: a plasma generationpart for pre-process gas configured to plasmarize the pre-process gas.3. The film formation apparatus of claim 1, wherein the pre-process gassupply part supplies the pre-process gas in the direction crossing therevolutional direction of the substrate mounting region.
 4. The filmformation apparatus of claim 1, wherein the other process regionsinclude a post-reaction region defined at a downstream side of thesecond region and at an upstream side of the first region when viewed inthe revolutional direction of the substrate mounting region, wherein thefilm formation apparatus further comprises: a post-process gas supplypart installed in the post-reaction region and configured to supply apost-process gas for modifying the thin film formed on the substrate. 5.The film formation apparatus of claim 4, further comprising: a plasmageneration part for post-process gas configured to plasmarize thepost-process gas.
 6. The film formation apparatus of claim 4, whereinthe post-process gas supply part supplies the post-process gas in thedirection crossing the revolutional direction of the substrate mountingregion.
 7. The film formation apparatus of claim 1, wherein the plasmageneration part for reaction gas includes a slot plate having aplurality of slots formed therein, through which microwaves are radiatedto a region to which a gas to be plasmarized is supplied, and adielectric plate installed between the rotatable table and the slotplate and configured to transmit the microwaves radiated from the slotplate therethrough.
 8. The film formation apparatus of claim 2, whereinthe plasma generation part for pre-process gas includes a slot platehaving a plurality of slots formed therein, through which microwaves areradiated to a region to which a gas to be plasmarized is supplied, and adielectric plate installed between the rotatable table and the slotplate and configured to transmit the microwaves radiated from the slotplate therethrough.
 9. The film formation apparatus of claim 5, whereinthe plasma generation part for post-process gas includes a slot platehaving a plurality of slots formed therein, through which microwaves areradiated to a region to which a gas to be plasmarized is supplied, and adielectric plate installed between the rotatable table and the slotplate and configured to transmit the microwaves radiated from the slotplate therethrough.